Leamington
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Leamington clear sky chart from 2005-11-05 to 2017-11-30.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
37%
15745
15%
47719
10%
15707
42%
15707
18%
33183

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
17%
879
10%
2489
4%
878
22%
878
12%
1973
January16th to endNight
17%
768
9%
2496
3%
768
24%
768
9%
1962
February1st to 15thNight
19%
701
9%
2284
3%
701
26%
701
12%
1739
February16th to endNight
24%
631
13%
1893
6%
631
31%
631
13%
1400
March1st to 15thNight
30%
720
15%
2049
9%
720
34%
720
17%
1476
March16th to endNight
36%
768
18%
2112
10%
768
43%
768
21%
1473
April1st to 15thNight
34%
632
14%
1830
8%
632
39%
632
20%
1284
April16th to endNight
38%
540
20%
1620
8%
540
47%
540
21%
1047
May1st to 15thNight
38%
540
13%
1620
7%
540
43%
540
17%
1130
May16th to endNight
49%
562
16%
1684
11%
561
53%
561
24%
1055
June1st to 15thNight
50%
384
16%
1370
15%
384
57%
384
22%
819
June16th to endNight
51%
408
18%
1308
14%
408
59%
408
25%
775
July1st to 15thNight
61%
510
16%
1360
15%
510
63%
510
34%
837
July16th to endNight
60%
564
17%
1577
14%
531
68%
531
36%
873
August1st to 15thNight
64%
539
20%
1609
16%
536
67%
536
32%
943
August16th to endNight
65%
573
24%
1719
17%
573
71%
573
33%
1003
September1st to 15thNight
59%
697
22%
1939
16%
697
62%
697
32%
1199
September16th to endNight
56%
717
24%
1980
17%
717
60%
717
30%
1243
October1st to 15thNight
45%
720
18%
2094
17%
720
47%
720
23%
1402
October16th to endNight
28%
768
16%
2361
10%
768
37%
768
17%
1667
November1st to 15thNight
35%
760
18%
2471
16%
760
40%
760
20%
1639
November16th to endNight
21%
780
12%
2637
7%
780
29%
780
11%
1945
December1st to 15thNight
18%
720
7%
2520
3%
720
23%
720
7%
2055
December16th to endNight
14%
864
7%
2697
1%
864
19%
864
8%
2244

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
13%7%36%5%35%5%5%7%35%
48659
Night
15%8%36%5%3445%6%35%
47901
Cloud CoverDay
13%7%36%5%345%5%7%35%
48669
Night
15%8%36%5%3445%6%35%
47905
TransparencyDay
45%5%13%21%11%1
48359
Night
49%412%20%11%1
47719
SeeingDay
15%10%15%28%22%6%
5972
Night
16%18%20%26%15%3
15753

By Month

Percentage Cloud Cover NE (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
19%14%5%8%6%37%35%6%18%
1446
16th to endDay
17%15%7%9%7%45%446%17%
1728
February1st to 15thDay
15%14%7%7%7%345%45%23%
1578
16th to endDay
14%11%5%10%7%34446%24%
1580
March1st to 15thDay
18%11%5%7%6%35%445%27%
1900
16th to endDay
17%10%5%7%6%34346%29%
2112
April1st to 15thDay
17%8%45%6%345%5%6%31%
2125
16th to endDay
17%5%35%5%24446%39%
2340
May1st to 15thDay
16%7%26%5%35%5%5%7%33%
2331
16th to endDay
11%5%24435%45%8%41%
2431
June1st to 15thDay
9%5%246%35%46%8%41%
2583
16th to endDay
9%425%5%35%6%7%11%37%
2646
July1st to 15thDay
8%424435%5%6%8%46%
2520
16th to endDay
8%4245%346%7%9%44%
2483
August1st to 15thDay
6%425%6%45%5%6%11%41%
2340
16th to endDay
9%4234345%7%9%45%
2483
September1st to 15thDay
11%6%245%2446%8%43%
2005
16th to endDay
12%5%25%4235%5%8%43%
1980
October1st to 15thDay
13%5%26%6%435%46%40%
1866
16th to endDay
19%7%25%5%345%5%6%33%
1861
November1st to 15thDay
14%7%36%3345%5%6%38%
1717
16th to endDay
16%10%48%6%35%5%5%6%27%
1646
December1st to 15thDay
19%10%6%10%7%45%5%5%5%19%
1440
16th to endDay
20%13%6%10%7%35%446%16%
1518
January1st to 15thNight
22%12%47%5%24445%24%
2489
16th to endNight
15%14%7%9%7%34445%22%
2496
February1st to 15thNight
16%13%5%8%6%43446%26%
2282
16th to endNight
17%11%48%7%34445%28%
1893
March1st to 15thNight
18%9%36%5%44446%31%
2037
16th to endNight
14%8%36%435%5%5%7%36%
2112
April1st to 15thNight
18%7%36%435%446%34%
1830
16th to endNight
13%6%25%5%35%5%5%7%39%
1620
May1st to 15thNight
18%6%26%5%35%5%5%7%32%
1620
16th to endNight
12%42443445%7%45%
1682
June1st to 15thNight
10%4245%35%6%7%7%43%
1370
16th to endNight
9%314426%5%6%10%43%
1308
July1st to 15thNight
7%3236%2445%8%51%
1440
16th to endNight
6%2144245%6%10%52%
1684
August1st to 15thNight
6%314335%6%5%9%48%
1620
16th to endNight
9%3233235%6%7%52%
1719
September1st to 15thNight
10%32442445%6%49%
1939
16th to endNight
11%5%245%23446%48%
1980
October1st to 15thNight
15%5%245%34347%41%
2094
16th to endNight
18%7%36%5%35%445%35%
2361
November1st to 15thNight
14%7%35%42445%6%40%
2471
16th to endNight
22%8%35%435%45%7%29%
2637
December1st to 15thNight
20%12%6%7%5%345%46%23%
2520
16th to endNight
23%13%6%9%7%34445%16%
2697

Percentage Cloud Cover SE (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
18%14%5%8%7%36%45%6%18%
1446
16th to endDay
16%15%7%10%7%45%45%5%17%
1728
February1st to 15thDay
15%13%7%8%6%35%45%6%22%
1578
16th to endDay
15%11%5%9%7%35%446%25%
1580
March1st to 15thDay
19%11%5%7%6%3445%6%27%
1911
16th to endDay
18%9%5%8%5%24346%30%
2111
April1st to 15thDay
16%7%5%6%5%346%47%31%
2125
16th to endDay
16%6%35%42445%6%39%
2340
May1st to 15thDay
16%6%35%6%345%5%7%34%
2331
16th to endDay
10%5%35%4345%5%8%43%
2431
June1st to 15thDay
10%5%25%5%25%5%6%9%42%
2583
16th to endDay
8%415%5%35%6%7%11%39%
2646
July1st to 15thDay
8%423435%5%6%8%47%
2520
16th to endDay
8%424425%5%6%9%46%
2483
August1st to 15thDay
6%4245%35%5%7%10%43%
2340
16th to endDay
9%3243245%6%9%47%
2483
September1st to 15thDay
11%6%24424448%44%
2005
16th to endDay
13%5%2443346%7%43%
1980
October1st to 15thDay
14%6%26%6%3445%5%40%
1866
16th to endDay
20%7%25%435%45%6%33%
1861
November1st to 15thDay
14%7%35%4345%47%38%
1717
16th to endDay
17%11%5%8%5%35%45%6%26%
1646
December1st to 15thDay
18%12%7%11%7%35%45%5%18%
1440
16th to endDay
20%14%6%10%8%34445%17%
1518
January1st to 15thNight
22%13%5%7%6%3444424%
2489
16th to endNight
16%15%7%9%6%3445%5%22%
2496
February1st to 15thNight
15%13%6%8%6%3445%5%26%
2275
16th to endNight
18%10%48%6%345%45%27%
1893
March1st to 15thNight
19%9%35%5%25%446%30%
2049
16th to endNight
15%7%36%4345%5%6%37%
2112
April1st to 15thNight
18%7%45%43445%6%34%
1830
16th to endNight
13%5%26%4345%5%7%40%
1620
May1st to 15thNight
18%6%25%5%36%5%6%6%32%
1619
16th to endNight
11%5%2443346%8%44%
1682
June1st to 15thNight
11%425%5%25%6%6%6%43%
1370
16th to endNight
8%424436%5%6%9%44%
1308
July1st to 15thNight
8%31443445%7%51%
1440
16th to endNight
6%31342446%9%52%
1684
August1st to 15thNight
6%314435%5%7%9%48%
1620
16th to endNight
9%323424447%52%
1719
September1st to 15thNight
11%31442445%6%49%
1939
16th to endNight
12%42443435%6%48%
1980
October1st to 15thNight
16%5%25%42435%8%40%
2094
16th to endNight
19%7%26%6%35%346%34%
2361
November1st to 15thNight
14%8%25%5%2445%7%39%
2471
16th to endNight
22%9%46%5%3345%6%27%
2637
December1st to 15thNight
21%13%6%7%6%345%46%20%
2520
16th to endNight
23%13%6%9%6%45%445%16%
2697

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
65%6%11%13%3
1447
16th to endDay
66%5%13%10%4
1728
February1st to 15thDay
61%5%10%16%6%
1580
16th to endDay
58%5%13%17%4
1580
March1st to 15thDay
56%6%12%16%6%
1911
16th to endDay
53%411%21%7%1
2112
April1st to 15thDay
49%5%13%18%12%
2125
16th to endDay
43%412%21%13%3
2340
May1st to 15thDay
46%6%11%21%11%2
2331
16th to endDay
36%6%13%27%13%1
2435
June1st to 15thDay
36%6%15%27%13%1
2583
16th to endDay
34%9%15%22%15%2
2646
July1st to 15thDay
31%5%11%28%19%2
2371
16th to endDay
32%6%16%26%15%2
2327
August1st to 15thDay
32%6%15%30%14%
2327
16th to endDay
31%6%15%27%16%2
2483
September1st to 15thDay
36%5%16%26%14%1
2005
16th to endDay
38%5%12%27%15%
1980
October1st to 15thDay
45%413%22%13%1
1866
16th to endDay
50%6%16%18%7%
1861
November1st to 15thDay
45%6%14%19%12%1
1717
16th to endDay
57%417%16%4
1646
December1st to 15thDay
68%5%12%10%3
1440
16th to endDay
68%5%11%11%2
1518
January1st to 15thNight
64%310%15%6%
2489
16th to endNight
65%412%14%3
2496
February1st to 15thNight
59%6%11%16%5%
2284
16th to endNight
58%311%20%6%
1893
March1st to 15thNight
53%412%20%8%1
2049
16th to endNight
47%411%23%10%2
2112
April1st to 15thNight
50%311%19%13%
1830
16th to endNight
42%410%19%16%5%
1620
May1st to 15thNight
49%5%11%18%11%2
1620
16th to endNight
37%6%11%26%15%2
1684
June1st to 15thNight
38%6%11%26%16%1
1370
16th to endNight
35%6%13%22%19%1
1308
July1st to 15thNight
31%6%10%26%22%2
1360
16th to endNight
26%6%17%25%20%3
1577
August1st to 15thNight
30%7%13%30%15%2
1609
16th to endNight
30%6%12%29%18%2
1719
September1st to 15thNight
35%5%13%25%17%2
1939
16th to endNight
37%411%26%19%1
1980
October1st to 15thNight
44%5%12%18%18%1
2094
16th to endNight
51%413%21%8%
2361
November1st to 15thNight
46%413%20%12%1
2471
16th to endNight
59%313%18%4
2637
December1st to 15thNight
69%49%12%4
2520
16th to endNight
71%411%10%3
2697

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
24%7%35%21%11%
90
16th to endDay
32%428%30%5%
96
February1st to 15thDay
21%436%31%6%
90
16th to endDay
20%225%38%12%
81
March1st to 15thDay
24%13%21%30%8%
201
16th to endDay
19%14%24%28%11%2
288
April1st to 15thDay
18%15%19%32%12%1
270
16th to endDay
16%14%22%26%14%5%
270
May1st to 15thDay
20%13%20%25%19%2
288
16th to endDay
12%11%13%29%27%5%
331
June1st to 15thDay
10%12%11%34%27%4
405
16th to endDay
11%14%13%34%22%3
495
July1st to 15thDay
8%10%8%32%32%7%
475
16th to endDay
7%11%5%28%36%10%
343
August1st to 15thDay
8%7%6%33%30%13%
313
16th to endDay
10%5%8%23%37%13%
332
September1st to 15thDay
12%6%9%23%30%16%
315
16th to endDay
17%6%9%16%31%18%
314
October1st to 15thDay
15%7%18%22%25%10%
315
16th to endDay
20%13%24%27%10%2
277
November1st to 15thDay
20%5%14%26%25%7%
135
16th to endDay
17%13%30%33%4
110
December1st to 15thDay
26%15%23%26%8%
60
16th to endDay
33%8%34%21%1
78
January1st to 15thNight
22%22%29%18%5%
883
16th to endNight
18%23%27%23%6%
768
February1st to 15thNight
20%19%29%25%4
704
16th to endNight
19%20%22%29%7%
631
March1st to 15thNight
19%20%21%29%8%
720
16th to endNight
16%19%21%29%11%2
768
April1st to 15thNight
18%19%21%31%8%1
632
16th to endNight
15%18%20%31%12%2
540
May1st to 15thNight
17%19%16%28%15%2
540
16th to endNight
10%18%13%29%23%5%
563
June1st to 15thNight
11%16%14%34%21%
384
16th to endNight
9%17%12%32%24%3
408
July1st to 15thNight
9%13%7%34%29%5%
510
16th to endNight
5%17%9%34%26%6%
564
August1st to 15thNight
7%11%9%35%28%8%
539
16th to endNight
9%9%9%27%36%8%
573
September1st to 15thNight
11%12%10%26%29%9%
697
16th to endNight
14%9%12%23%29%10%
717
October1st to 15thNight
19%12%17%22%22%5%
720
16th to endNight
19%18%29%24%7%
768
November1st to 15thNight
16%19%23%25%12%2
760
16th to endNight
24%25%25%16%8%
780
December1st to 15thNight
25%25%25%16%5%
720
16th to endNight
22%24%29%19%3
864
Page generated at 2017-12-01 12:13:42. Version ac04

Copyright 2017 A. Danko


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